Effects of ground plane and dielectric truncations on the efficiency of a printed structure

Effects of ground plane and/or dielectric truncation on the radiation efficiency of a printed radiator are studied. A closed-form expression for the reflection coefficient of surface wave modes from the truncated edge is obtained. Numerical results for the reflection coefficient and the radiation efficiency are discussed, and radiation patterns for various dielectric constants, substrate thicknesses, and ground plane dimensions are presented. It is found that for certain ground plane dimensions the radiation efficiency is considerably lower than normal; these dimensions should be avoided to reduce the surface wave loss.<
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